Monday, June 08, 2015

Octopus Carries Coconut—But Is It Using a Tool?

A viral video shows an octopus toting a coconut as a ready-made shelter, which some biologists call tool use. But not everyone is convinced.
When hunting for tasty morsels like crabs and scallops, octopuses must watch out for predators at all times. That's why some of these brainy, eight-legged creatures bring along ready-made body armor—sometimes in the form of coconuts.
In the video (above) that recently went viral, an octopus trudges along the ocean floor carrying two halves of a coconut. Suddenly it stops, pulls them together and climbs inside.
Scientists have known about this behavior for a while, but it was first filmed in 2009 in North Sulawesi, Indonesia, by a team of biologists from Museum Victoria in Melbourne, Australia.

Tool Debate:
For a long time, scientists thought only people used tools, but ongoing research reveals that other animals do it too.
Examples include chimpanzees sliding twigs into a termite mound to access juicy treats, bottlenose dolphins using sponges to dredge prey from the ocean floor, and bearded capuchin monkeys cracking nuts with rocks.
Though there's no single definition for what constitutes tool use, Finn says the coconut-carrying is an example. That's because the octopuses are gathering and assembling coconut shells with the foresight that they may need them in the future.
But others, such as marine biologist James Wood, are a bit more skeptical.

"My house isn't a tool for me—it's my house," says Wood, "But if I need a hammer or a screwdriver to put up drywall, that is a tool."
Wood believes a tool is an object used by an animal to interact with and change their environment.
"if you're going to say [the coconut-carrying octopus is] tool use, then anything that carries or uses another object for protection would then be using tools," he says. "You have to draw the line somewhere."
But Jennifer Mather, a professor of psychology and neuroscience at the University of Lethbridge in Alberta, Canada, argues octopuses use tools. She's studied how octopuses shoot water jets to clear dens of sand and grit and stack rocks in front of the openings.
"It's clear that there is no single way of using tools," she says. "It's a fascinating behavior, but it's not a unitary behavior."
Regardless of where a scientist stands on the tool question, it's indisputable that octopuses are "masters at manipulating and mimicking their environment," says Finn, the biologist who filmed the original coconut-carrying octopus.
Unlike mollusks such as clams, octopuses don't have a hard shell to protect them from predators—so they need to be creative to survive. Some change colors to blend into their surroundings with remarkable accuracy, and many more shoot ink when threatened.
As for the coconut-carrying behavior, it could be a way for an octopus to feel safe while it's out in the open, Wood adds. The octopus in the new video is seen walking exposed on the seafloor—not an ideal locale. Octopuses spend much of their life in lairs, which they dig under coral reefs or fashion in rocky outcroppings.
"They don't starve to death and they don't tend to die of diseases," says Wood the marine biologist.
"They almost always get eaten."﻿